The general objective of this project is to study the mechanism(s) of the antitumor effect of glycolipid A1 which has been recently isolated and purified from Mycobacterium bovis BCG in these laboratories. Glycolipid A1 dissolved in olive oil is a very strong granulomagenic agent in the skin of guinea pigs and when administered simultaneously with cancer cells is able to abrogate tumor growth. It is speculated that glycolipid A1 controls tumor growth by a nonimmune mechanism(s) in which macrophages present in the inflammatory reaction play a crucial role.